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Candidiasis is infection by Candida sp (most often C. albicans), manifested by mucocutaneous lesions, fungemia, and sometimes focal infection of multiple sites. Symptoms depend on the site of infection and include dysphagia, skin and mucosal lesions, blindness, vaginal symptoms (itching, burning, discharge), fever, shock, oliguria, renal shutdown, and disseminated intravascular coagulation. Diagnosis is confirmed by histopathology and cultures from normally sterile sites. Treatment is with amphotericin B, fluconazole, echinocandins, voriconazole, or posaconazole.
(See also the Infectious Diseases Society of America’s Guidelines for treatment of candidiasis.)
Candida sp are commensal organisms that inhabit the GI tract and sometimes the skin (see Candidiasis (Mucocutaneous) : Etiology). Unlike other systemic mycoses, candidiasis results from endogenous organisms. Most infections are caused by C. albicans; however, C. glabrata (formerly Torulopsis glabrata) and other non-albicans species are increasingly involved in fungemia, UTIs, and, occasionally, other focal disease. C. glabrata is frequently less susceptible to fluconazole than other species; C. kruseiis inherently resistant.
Candida sp account for about 80% of major systemic fungal infections and are the most common cause of fungal infections in immunocompromised patients. Candidal infections are one of the most common hospital-acquired infections.
Candidiasis involving the mouth and esophagus is a defining opportunistic infection in AIDS. Although mucocutaneous candidiasis is frequently present in HIV-infected patients, hematogenous dissemination is unusual unless other specific risk factors are present (see below). Neutropenic patients (eg, those receiving cancer chemotherapy) are at high risk of developing life-threatening disseminated candidiasis.
Candidemia may occur in nonneutropenic patients during prolonged hospitalization. This bloodstream infection is often related to one or more of the following:
IV lines and the GI tract are the usual portals of entry. Candidemia often prolongs hospitalization and increases mortality due to concurrent disorders. Prolonged or untreated candidemia may lead to endocarditis or meningitis as well as to focal involvement of skin, subcutaneous tissues, bones, joints, liver, spleen, kidneys, eyes, and other tissues. Endocarditis is commonly related to IV drug abuse, valve replacement, or intravascular trauma induced by indwelling IV catheters.
All forms of disseminated candidiasis should be considered serious, progressive, and potentially fatal.
Esophageal candidiasis is most often manifested by dysphagia.
Candidemia usually causes fever, but no symptoms are specific. Some patients develop a syndrome resembling bacterial sepsis, with a fulminating course that may include shock, oliguria, renal shutdown, and disseminated intravascular coagulation.
Candidal endophthalmitis starts as white retinal lesions that are initially asymptomatic but can progress, opacifying the vitreous and causing potentially irreversible scarring and blindness. In neutropenic patients, retinal hemorrhages occasionally also occur, but actual infection of the eye is rare.
Papulonodular skin lesions may also develop, especially in neutropenic patients, in whom they indicate widespread hematogenous dissemination to other organs. Symptoms of other focal infection depend on the organ involved.
Because Candida spp are commensal, their culture from sputum, the mouth, the vagina, urine, stool, or skin does not necessarily signify an invasive, progressive infection. A characteristic clinical lesion must also be present, histopathologic evidence of tissue invasion (eg, yeasts, pseudohyphae, or hyphae in tissue specimens) must be documented, and other etiologies must be excluded. Positive cultures of specimens taken from normally sterile sites, such as blood, CSF, pericardium, pericardial fluid, or biopsied tissue, provide definitive evidence that systemic therapy is needed.
Serum β-glucan is often positive in patients with invasive candidiasis; conversely, a negative result indicates low likelihood of systemic infection.
Ophthalmologic examination to check for endophthalmitis is recommended for all patients with candidemia.
In patients with invasive candidiasis, predisposing conditions (eg, neutropenia, immunosuppression, use of broad-spectrum antibacterial antibiotics, hyperalimentation, presence of indwelling lines) should be reversed or controlled if possible. In nonneutropenic patients, IV catheters should be removed.
When an echinocandin is indicated (if patients are moderately severely ill or critically ill [most neutropenic patients] or if C. glabrata or C. krusei is suspected), one of the following drugs can be used: caspofungin, loading dose 70 mg IV, then 50 mg IV once/day; micafungin 100 mg IV once/day; or anidulafungin, loading dose 200 mg IV, then 100 mg IV once/day.
If fluconazole is indicated (if patients are clinically stable or if C. albicans or C. parapsilosis is suspected), loading dose is 800 mg (12 mg/kg) po or IV once, followed by 400 mg (6 mg/kg) once/day.
Treatment is continued for 14 days after the last negative blood culture.
Esophageal candidiasis is treated with fluconazole 200 to 400 mg po or IV once/day or itraconazole 200 mg po once/day. If these drugs are ineffective or if infection is severe, voriconazole 4 mg/kg po or IV bid, posaconazole 400 mg po bid, or one of the echinocandins may be used. Treatment is continued for 14 to 21 days.
Unlike other fungal infections, invasive candidiasis is usually due to endogenous organisms.
Invasive infection typically occurs in immunocompromised and/or hospitalized patients, particularly those who have had surgery or been given broad-spectrum antibiotics.
Positive cultures of specimens taken from normally sterile sites (eg, blood, CSF, tissue biopsy specimens) are needed to distinguish invasive infection from normal colonization; serum β-glucan is often positive in patients with invasive candidiasis.
Use an echinocandin if patients are severely or critically ill or if infection with C. glabrata or C. krusei is suspected.
Use fluconazole if patients are clinically stable or if infection with C. albicans or C. parapsilosis is suspected.
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